"What?" This time Dirk looked round, irritably.

"Or just a fag, mate. Got a fag you can spare?"

"No, I was just going to go and get some myself," said Dirk.

The man on the pavement behind him was a tramp of indeterminate age. He was standing there, slightly wobbly, with a look of wild and continuous disappointment bobbing in his eyes.

Not getting an immediate response from Dirk, the man dropped his eyes to the ground about a yard in front of him, and swayed back and forth a little. He was holding his arms out, slightly open, slightly away from his body, and just swaying. Then he frowned suddenly at the ground. Then he frowned at another part of the ground. Then, holding himself steady while he made quite a major realignment of his head, he frowned away down the street.

"Have you lost something?" said Dirk.

The man's head swayed back towards him.

"Have I lost something?" he said in querulous astonishment. "Have I lost something?"

It seemed to be the most astounding question he had ever heard. He looked away again for a while, and seemed to be trying to balance the question in the general scale of things. This involved a fair bit more swaying and a fair few more frowns. At last he seemed to come up with something that might do service as some kind of answer.

"The sky?" he said, challenging Dirk to find this a good enough answer. He looked up towards it, carefully, so as not to lose his balance. He seemed not to like what he saw in the dim, orange, street-lit pallor of the clouds, and slowly looked back down again till he was staring at a point just in front of his feet.

"The ground?" he said, with evident great dissatisfaction, and then was struck with a sudden thought.

"Frogs?" he said, wobbling his gaze up to meet Dirk's rather bewildered one. "I used to like...frogs," he said, and left his gaze sitting on Dirk as if that was all he had to say, and the rest was entirely up to Dirk now.

Dirk was completely flummoxed. He longed for the times when life had been easy, life had been carefree, the great times he'd had with a mere homicidal eagle, which seemed now to be such an easygoing and amiable companion. Aerial attack he could cope with, but not this nameless roaring guilt that came howling at him out of nowhere.

"What do you want?" he said in a strangled voice.

"Just a fag, mate," said the tramp, "or something for a cup of tea."

Dirk presse d a pound coin into the man's hand and lunged off down the street in a panic, passing, twenty yards further on, a builder's skip from which the shape of his old fridge loomed at him menacingly.

As Kate came down the steps from her house she noticed that the temperature had dropped considerably. The clouds sat heavily on the land and loured at it. Thor set off briskly in the direction of the park, and Kate trotted along in his wake.

As he strode along, an extraordinary figure on the streets of Primrose Hill, Kate could not help but notice that he had been right. They passed three different people on the way, and she saw distinctly how their eyes avoided looking at him, even as they had to make allowance for his great bulk as he passed them. He was not invisible, far from it. He simply didn't fit.

The park was closed for the night, but Thor leapt quickly over the spiked railings and then lifted her over in turn as lightly as if she had been a bunch of flowers.

The grass was damp and mushy, but still worked its magic on city feet. Kate did what she always did when entering the park, which was to bob down and put the flats of her hands down on the ground for a moment. She had never quite worked out why she did this, and often she would adjust a shoe or pick up a piece of litter as a pretext for the movement, but all she really wanted was to feel the grass and the wet earth on her palms.

The park from this viewpoint was simply a dark shoulder that rose up before them, obscuring itself. They mounted the hill and stood on the top of it, looking over the darkness of the rest of the park to where it shaded off into the hazy light of the heart of London which lay to the south. Ugly towers and blocks stuck yobbishly